I've considered doing this, myself, before, but never got around to it. I didn't think it would work out too well. But this is pretty damned good, so maybe I was wrong.
Took a lot of work. Around 3h for one page ... unless there's only one sentence or moaning sounds to translate. The complete Manga took a little bit longer than my last manip - however, I still think it was worth it. There were so many ppl that wanted it translated and even more that never saw this manga.
I am doing this in 5 Phases.
1. Get the Hiragana/Katakana/Kanji's into a text file with an OCR Program (and if this fails I have sites were I can search for the Kanji) <- Takes most of the time, but everyone can do this
2. Get a rough translation of the sentence by using 5 different Translation sites. Then looking at the sentence word by word and trying to make sense of it and then find a fitting sentence in english. This is actually a multipass thing - you do this over and over again. When you finish with the manga, you start from the beginning again and correct things (because you might have found out something later in the story that is mentioned earlier, but you couldn't make sense of it then).
3. Clean up the images and remove the Japanese signs. Redrawing certain areas or making a workaround if possible.
4. Typesetting. Actually entering the translation into the Text bubbles, making them fit and not look akward.
5. Quality Assurance. Reading the Manga over and over again, correcting mistakes, moving the text that doesn't look like it fits well. Correcting translation if something looks akward or doesn't make sense etc.
It's a lot of work for one person and I think the translation groups easily split the work between 2-4 people which makes it a lot easier.
So, if you don't want to put 60 hours into a 20 Page Manga (well, you will improve over time and it will probably get a lot faster). I didn't know basic Hiragana when I started but now I am getting better at it. I also got a couple of basic Kanji that I now understand. I think it is a good method to get into the japanese language and actually learn something - I just do not know if it is the best method to learn it. I should probably learn a couple of more basic stuff from my Japanese book before I do the next translation. :)